DR2 DQWL INHERITANCE AND HAPLOTYPE SHARING IN AFFECTED SIBLINGS FROM MULTIPLE-SCLEROSIS FAMILIES/

Although the human leukocyte antigen DR2/DQw1 allele has been associat ed with multiple sclerosis, studies of DR2/DQw1 inheritance in multipl e sclerosis multiplex families have yielded conflicting results. We ex amined this question in ''high-incidence'' families, defined as famili es with more than 50% of siblings affected. DR2/DQw1 allele frequencie s were significantly increased, particularly in mothers and affected s iblings (p < 0.0001). The transmission of DR2/DQw1 from both parents w as more frequent in affected offspring (p = 0.005). While evidence for segregation of disease with a particular parental allele was lacking in most families, the frequency of haplotype sharing was higher in aff ected sib pairs (p < 0.01).